Shot firer



June 8 1926.

M. L. MCGRAW SHOT FIRER Filed Sept. 26. 1935 2 Sheets-Sheet 1 Patented June 8, 1926.

snow FIBER.

Application filed September 26, 1925. Serial No. 58,933.

The object of my invention is to provide a novel and etiicient machine for use in a of Fig. 4; and

been clamped. in its hole drilled for firing explosives. I attain this and other objects of my invention by the device illustrated in the accompanying drawings, in which-- Figure 1 is a side elevation of the invention in its initial position before ope-ration; Fig; 2 isa side elevation of the invention in its expanded position caused by its operation;

Fig. 3 is a detail perspective view of member 14;;-

Fig. 4 is a longitudinal section through the device;

Fig. 5 is a transverse section on line 5--5 Fig. 6 is a transverse section on line G -6 of Fig. 4.

Like characters of reference designate like parts in each of the several views.

Referring. to the accompanying drawing, A indicates a hole drilled in the earth in which is placed an explosive charge B to be fired by a spark generated by the electric wires G a'iterthe shot firing device has place in the earth, as shownin Fig. 2. As indicated in the drawings, TI provide a firing tube 5 havinge tapered or frusto-conical head 18, the in- :terior of which is in threaded engagement with the treaded portion 9 of rod 7, as indicated in Figs. 1 and 2. I provide suitable handle 6 on rod 7. Rod 7 is also provided with an annular flange 11 and with a threaded portion 10 threaded inreverse direction from the threaded portion 9 I provide a pair 0t semi-cylindrical resistant arcs 11 and 15 having-an annular groove 12 in which the annular flange 11 seats. I frusto-conical tubular end screw 19 threaded on threaded portion 10 of rod 7. Members 14 and 15 have a "beveled inner surface 2-1 at the point where they contact with tapered members 18 and 19, as "ndicated in Fig. 4. Anchor members 14 and 15 are provided with spaced annular teeth or projection rings 16; and teeth or projection rings 16 are, in turn, provided with apertures 17. I provide springs 20 encircling anchor members 14 and 15 and resiliently holding "them in proximity to each other. between arcs Hand 15 and seated 1n slot I provide a "key 22 positioned 21in member18yas shown in Fig. 6. I

also provide similar key 24 positioned between members-14c and 15 and seated in a similar slot 23 in member 19. I provide a tube 25 between members 1 1 and 1-5., as shown in Figs. 5 and 6 and welded to one of those members for the purpose of holding the wire leading to the charge of powder. WVhen the handle on one end of the fining rod is turned and the pressure pipe held stationary the keys on the pressure pipe and the tubular end screw being engaged abetween the resistant arcs prevents the end screw from turning. The right and leitt hand threads'on the firing rod moving in {the threads in'the end screw and the :pressure pipe bring them towards one another, thereby forclng the anchor members outwards against the pressure of the spring or springs surrounding the resistant arcs.

The projection rings on the resistant arcs being thereby forced outwards will bury themselves in the walls or" the hole in which the machine is placed, thus blocking it up so that the charge will take effect as desired.

After the shot is fired in order to bring the resistant arcs in position to get the machine hole where the charge is tobe fired, the handle on the firing rod must be turned in the opposite direction so that the spring or springs can force the resistant arcs into a smaller diameter over all by drawing the frusto-conical end screw away from the anchor members.

The firing rod can be made of steel or other suitable material. It is a round rod of any diameter and length to suit any particular condition. (Fine end of the rod is bent to make some convenient handle for turning. At the other end threads are run to suit length of anchor members from the end, then a short blank space, and, threads run in the opposite direction for .adistance suitable to conditions.

The pressure pipe can be made. of steel, iron, or other suitable material. The pressure pipe fits loosely around the firing rod and is a few inches shorter. llhe end nearest the explosive is threaded for a few inches and made smaller than the regular pipe diameter in order that the threads may engage the threads in the firing rod. These threads are opposite in direction to the threads in the end screw and at the end of the firing rod. The outside diameter of the end next-to the explosive is enlarged a short distance back and tapers with a smooth curve to the end, in order that when the firing rod is turned .andthepressureipipe held stationary the resistant 1 arcs willfbe 7' The anchor members may be made ofiron,

'steel or'any other suitable material and are two in number. They operate around the firing rod between the pressure pipeand the,

eons of the'a-n'chor; membersyin a straight -line, torece1ve-the SlIOOtlI Ig WIIGS. The outside edge *of the inside anchor members is. .bevel ed to the same curvature-as the curvet tapersat the enlarged endsdo-f 'the pressure J pipe and the end.- screw 'inorderthat; they may slide overonecanother'as easily as'pos-f -sib1eJ "i 7' 1 1.. The anchor members springs surround the resistant arcsand'hold them. in] place. 'lh'ey t may be either coil; or band springs of any size required, *ofany suitable material and.

one less-ln-numb'er than: there are projec- The end screw may-be made ofziron, steel;

Lori.-otherv suitabl e material; Y It isa small round piece of material drilled in the center [andthreadedtoifit over theend offthe fir} ing frod.'. J The surface next to the explosive sistant arcs may slide over this when the end rafpa-ir of anchorvmembfers of approximately turning the firing arm. 7 7 The end screw and thepressure pipekey Y "are small projections from 'theplaneof the screwis vdrawn into. the resistant arcs by taperifon the .endscrew and pressure pipe threaded portion of thGLI'Od above 'the anthreaded; engagement with the theaded por 'tion of the rod below the} annular flange;

semi-circular sha'pe haying their end :por-

nag u -e In a shot firery the combination "said tubular 'mem'ber'havingafrustroconieal e head inthreadedengagement withthe thead portlongofthe-rodabovethe annular flange;

gagement; with *the theadedsportion' of the I m j rod; below the; annular gflan ge; a pa-ir fof} "isifiat and tapered back tothe opposite end Iwith a-smoot-h slight taper; so 'thaththe re the semii-cylindrieal members toward; each 1. In a shot'firerithe combination-ofa'rodz; l i'havi ngfa handle at oneend and having an annular flange near the other end, and having oppositely disposed threaded "por "tions on each 'side-ofsaid'flange, a-tubular member within which the rod is mounted 7 said tubular member having a frustdconi-"f eal head in threaded engagementi-withthe 160 m V I m ;theisemi-circular members towardeachotheq n-ular flange, ia frusto comca-l' end screwln ringsp q v H r v p m In a shot firer, the combination of arod i tions engaging the 'tapered' wallsioifthe frusl f o tc-conical members, and resilient means,

pressing the semicylindrical m'embersto? wards each'other.

In a'shot area; theicombination eerie" rod having a handle-at one end,-ja nd'hav-1ng't gfan annular flange near the other en'd," an'cl "having oppositelydisposed i threaded pjor-fv end screw and are each ailittl'eless than a "semi-circle, in, orderfto leave a' space between V. them'on each side, Therearetwo or more {projection rings around theou'tsid'e' 0f the a anchor members tapered at theoutward edgei "sothat they will penetrate thewalls of the' holes as easilyas possible. Thereis a' small hole drilled through the proj ection rings {of 'tions on each-side, of said flange; aj iftubular m b Withi whi hsth r ad: is m ed.

head in threaded} engagemntjwith [the ,tions'engagingthe tapered'wallsiof it m 7 to -conicalmembers; resilient meanspressing an sp c p ph rie tap re rings on the "resistant arcs."

rod having a 'handlejat one end, andlhaving an an nular flange near ,they other end, and

having. oppositely disposedjthreaded fpon tions on each'side of said; flange-1a tubular member within which-the; rod' isfmounted a 'frusto-conical end-"screw in threaded en'- anchor 2 members of approximatelj: semi cyeonieal. members, f resilient means; pressing other, keys projecting {from the -frusto-conical" s e n figagingfbetweeni the semi p cylindrical members; I

respectively,'that engage 'betweenthe' open ingsbietweenthe resistaneearcsQ Thus whenwthexpressure pipe, is heldgstationary the'keys' Khold theresistant arcszand the endscrew ,from -revolving when the'firing rod is turned;

Key's 222and' 25Lare either welded'into place are integral with m'emb'erslB and 19.3

441 a sh fire ith J mb fiq ildfa 'Q r evihga hw l e at ne en ai end h vi an; annular, flange an'ear-jthe other; end, and

v n ppos ly,fd spv dt r ded ll-9 ftionsjon each sidebf sfaidg-fiange,Ia'tubular lg n member within whichk the; rod is mounted, T

; said tubular member? having a frustoconicalt head-Qinj, threaded engagement with ithex i' fthread'ed fportion ef; the {rod above? the an 1 i nular' flange,--a; frusto conical end screw in; f;

treaded engagement{with the threadedfp or-fmo pairof anchor members of approximately} 1 semicircular shape .ha ingJtheir;endporf, ii at ti ns-engaging. the tapered walls of the frus- J tion of the rodbelow, thetannular-flange; a

to-conical 'IIIBmbfQISQfIBSiliBIIfi means pressing l on the resistantarcaijand a series of alined apertures throughathe spaced f projection said'tubula-r member havingafrustobonical 85 the semicircular members toward each other,-, m pro ectlon 1 its; 7

having a handle at one end, and having an annular flange near the other end, and having oppositely disposed threaded portions on each side of said flange, a tubular member within which the rod is mounted said tubular member having a frusto-conioal head in threaded engagement with the threaded portion of the rod above the annular flange, a frusto-conical screw in threaded engagement 10 with the threaded portion of the rod below the annular flange, a pair of anchor members of approximately semi-cylindrical shape having their end portions engaging the tapered walls of the frusto-conical members, the semi-cylindrical members having alined semi-circular grooves in which the annular flange on the rod is adapted to seat, and resilient means pressing the semi-cylindrical members toward each other.

MICHAEL L. NICGRAV. 

